Laser steering of particle beams: refraction and re#ection of particle beams

The co-propagation of an intense particle beam with an ionizing laser beam in a working gas/plasma is considered. When the axes of the laser and particle beam are not aligned, then asymmetric plasma lensing results in a net dipole "eld acting on the particle beam. The particle beam can be steered or bent (as well as focused) by steering the laser. An analogy is made between the bending of the particle beam by collective e!ects at a plasma boundary and the refraction or re#ection of light at an interface. This mechanism of particle steering may be of interest in applications for which permanent magnets are inconvenient or a fast turn on is required. 3-D particle-in-cell simulations and relevance to a recent experiment are discussed. ( 2000 Elsevier Science B.V. All rights reserved.